The present invention relates to paver vehicles and compactor vehicles, and more specifically to systems for monitoring and controlling paver vehicles and compactor vehicles used for forming asphalt mats.
Paver vehicles or xe2x80x9cpaversxe2x80x9d capable of forming mats of material, such as asphalt, upon a base surface are well known. Such paver vehicles basically consist of a tractor and a screed assembly towed by the tractor. The tractor includes a tractor body and wheels and/or a pair of continuous tracks mounted to the tractor body for mobilizing the tractor to travel upon a base surface. The tractor also generally includes an operator station and a material hopper mounted to the front end of the tractor for holding a quantity of paving material. Further, a conveyor extends longitudinally between the hopper and the rear of the tractor and functions to transport paving material from the hopper to be deposited off the rear of the tractor. A rotatable auger is mounted to the rear of the tractor and operates to spread deposited paving material laterally across the base surface to form a head of paving material in front of the screed.
The screed assembly functions to level and compress the material head to form a continuous formed material mat on the base surface, generally in the form of an elongated strip, as the tractor travels forwardly upon the base surface. The screed assembly includes a main or primary screed and may include one or more extensions attached to the main screed, which may be fixed or extendable with respect to the main screed. The main screed and any extensions each include an upper frame and a lower screed plate attached to the frame, the screed plate providing the working surface for leveling (i.e., establishing formed material mat thickness), and generally also compressing, the paving material into a formed material mat.
Typically, the screed assembly includes one or more vibrators mounted on the upper surface of the screed plates which function to increase the compression or compressive force applied by the screed plates to the formed material mat during the leveling operation. Certain paver vehicles, particularly those used in countries where xe2x80x9clow speedxe2x80x9d paving is preferred, include one or more reciprocating tamper bar that are disposed forwardly of the screed plates. The tamper bars function to pre-compress the paving material prior to leveling by the screed plates.
In addition, many screed assemblies are provided with one or more mechanism(s) referred to as xe2x80x9cscreed assist device(s),xe2x80x9d which includes one or more hydraulic cylinders having a first end connected with the tractor and a second end connected with the screed assembly. These screed assist device(s) are used to raise and lower the screed assembly with respect to the base surface, and can be operated so as to increase or decrease the compressive force exerted by the screed plates on the formed material mat by appropriate vertical displacement of the entire screed assembly (and thus also the screed plates).
Further, compactor vehicles or xe2x80x9ccompactorsxe2x80x9d are also well known. Typically, compactor vehicles used with asphalt material mats include a vehicle body and a pair of drum members or xe2x80x9cdrumsxe2x80x9d rotatably mounted to the body. Such compactor vehicles generally function by rolling over sections of the formed material mat such that the drums compact the formed material mat with every pass made over a particular section of the formed material mat, the drums also functioning to mobilize the compactor vehicles. Typically, a vibratory mechanism is mounted within each drum to increase the extent of formed material mat compaction made by each pass of the drums. These vibratory mechanisms are generally variable in frequency and amplitude, variations in frequency enabling the compactor to be effectively operated at different speeds and variations in amplitude affecting the degree of compaction made by the drums.
In a typical project for forming an asphalt mat, such as in roadway constructions, the paver vehicle forms a continuous mat of material behind the paver vehicle as the paver vehicle travels forwardly upon the base surface. One or more compactor vehicles follow the paver vehicle and generally roll over all sections of the formed material mat until the formed material mat is compacted to a desired degree or extent.
Preferably, the formed material mat is formed such that the material is within a desired temperature band. If sections of the formed material mat are at a lower than preferred temperature, compactor(s) may have to make additional passes across these sections to ensure sufficient compaction. On the other hand, if sections of the formed material mat are at a higher than preferred temperature, compactor operators will have to take caution to avoid over compacting these sections.
If would therefore be desirable to provide a system to monitor the temperature of the formed material mat as the formed material mat is being formed such that the temperature information may be used by an operator of a paver vehicle or a compactor vehicle to make appropriate adjustments to the operational parameters of the paver vehicle or compaction vehicle. Further, it would be desirable to provide a system for readily identifying sections of a formed material mat that may require additional compaction or sections of a formed material mat where it may be necessary to compact with greater caution. Furthermore, it would be desirable to provide a system for using formed sensed material mat temperature information to automatically adjust paver vehicle or compactor vehicle to provide an acceptable formed material mat.